Method of fabricating and locally reinforcing panels, casings, or covers



8, 1956 E H. VOELKER 2,760,898

METHOD OF FABRICATING AND LOCALLY REINFORCING PANELS, CASINGS OR COVERS Original Filed April 12, 1949 z z m /3/ 6 ,2/

F 3 /6 t k g) :2: 1,2/

INVENTOR. Edward H. 06 Mar A TTORNEY.

of the latter will not be reduced or materially affected by the reinforcements.

It will be evident that the subject construction is not limited in its application to any particular article made of synthetic resin but can be applied with equal facility to articles of any shape, contour or size and employed for any purpose or function. To illustrate a representative application or adaptation thereof, a transparent cover or casing for the navigation light of an airplane located at a wing tip has been selected as an example.

Reference being had more particularly to the drawing designates a cover or casing fabricated of transparent acrylic resin. This cover is here illustrated as located at the tip of the wing 11 and incorporated in the leading edge thereof to enclose the naviation light usually located at that point. A casing or cover 11 of this type forms a continuation of the wing and therefore, is hollow and generally U-shaped in section whereby the opposed surfaces 10' thereof can rest in the planes of and respectively form coplanar continuations of the top and bottom skins 12 of the wing. The internal structure of the wing 11 Where the cover or casing 10 is to be located, is so constructed or modified that the space enclosed by the casing or cover is defined on two sides viz; the sides thereof adjoining the main body of the wing by ribs, spars or similar elements 13 disposed under the skin 12 of both the upper and lower surfaces of the wing.

This modification or construction of the wing tip forms no part of the present invention beyond providing a coacting structure for the support and attachment of the cover fabricated in accordance with this invention. Manifestly, any type of support or supporting structure may be provided so long as it includes complemental means for coacting with the fastening or attaching means piercing the panel, casing or cover made as taught herein and to beassociated with the selected supporting or mounting structure.

These ribs or spars 13 are pierced at intervals by the apertures 14, and positioned on the inner surface of each such rib or spar 13 in registration with each aperture 14 isprovided a plate nut 15 riveted or otherwise fixedly secured flush against the cooperating spar or rib 13.

The edge portions of the top and bottom sides 10 of the cover 10, when the latter is in its operative position, overlie and rest flush against the outer surfaces of the spars or ribs 13 of the wing structure defining the space enclosed by said cover and the outer surfaces thereof form flush continuations of the associated wing skin 12. In alignment with each aperture 14 and plate nut 15 the edge portion of the casing is provided an enlarged or oversized opening 16, within which is seated a washer or button 17 pierced concentrically by a passage 18 for the reception of suitable mounting or attaching means. This passage 18 in the washer or button 17 is in direct registration with the threaded passage of the aligned plate nut 15 so that these two passages in effect constitute a continuation one of the other and of the aligned aperture 14 in the rib or spar 13. At its outer end the button 17 is countersunk, as at 19, concentric to the passage 18 therein for the reception of the head of the mount ing screw, bolt 01' rivet 29. As will be hereinafter more fully described in conjunction with the construction and method of making the casing or cover 10, the button or washerl! is fully reinforced and in its operative position comprises a homogeneous mass with a surrounding body of synthetic resin from which the cover or casing 10 is made.

Disposed along the edge of the inner surface of each side 10 of the casing or cover 1% is a reinforcing tape or strip 21. This strip is continuous and lies below an entire line or row of openings 16 and the several buttons or washers 17 seated therein along the edge portion of a side 10 of the cover or casing. For the passage of the attaching screws, rivets or bolts through this reinforcing strip 21, it is apertured in alignment with the i threaded opening of the plate nut 15, the opening 14 in the rib or spar 13 and the opening 18 of each button or washer 17.

From the foregoing it is clear that, when the cover 10 is positioned so that its edge portions overlie the spars or ribs 13 of the wing structure defining the space enclosed by the cover 1% the apertures 18 in the several buttons or washers 17 adjoining the edge thereof and the aligned openings in the reinforcing strip 21 are in registration with the corresponding apertures 14 of the spars or ribs 13. When this alignment or registration is established the screws 20, or other suitable fastening means, may be inserted in and projected through these aligned openings whereby their threaded extremities 22 may engage the internally threaded openings of the plate nuts 15. Each screw 20 may then be threaded inwardly of the plate nut 15 until its head is snugly seated in the countersink 19 in the outer face of the button or washer 17. Thus the button or washer 1'7 is clamped between the rib or spar 13 on one side and the head of the screw 20 on the other-side and the reinforcing strip 21 is dis posed and held between the edge portion of the cover 10 and the adjacent surface of the rib or spar 13. All of the clamping or engaging pressures are therefore trans-- mitted to and through the buttons or washers 17 to the reinforcing strip 21 and from it to the rib or spar 13.

In order to combine the several buttons or washers 17 with the adjoining reinforcing tape or strip 21 and both. the buttons and strip in an integral and homogeneousassembly with the resin of the casing or cover 10, each button or washer 17 as well as each strip or tape 21 comprises a plurality of layers of fiber glass or cloth laminated and impregnated throughout with the same resin as that used in the fabrication of a cover or casing 14). In this manner each button or washer 17 consists of a plurality of fiber glass or cloth layers laminated and impregnated throughout with acrylic resin having a thickness when cured substantially equal to the thickness of the sides 10', of the cover it The tape or strip 21 also consists of a plurality of fiber glass layers laminated with acrylic resin to any desired thickness.

Before the buttons or washers 17 and the reinforcing strips 21 are assembled in their operative positions they are first immersed in a cement consisting of acrylic resin (the resin from which the casing or cover 10 is fabricated) dissolved in a suitable solvent such as acetone. Thus, the resin of the buttons 17 and tape 21 as well as the abutting surfaces of the cover 10 are softened .by the aforesaid cement, and as the solvent of the cement evaporates there is an intermingling of the resins of the buttons and tape with each other and with the resin of the cover at all points of contact. This results in a unitary and homogeneous mass or body of resin in the cover 10, restricted areas of which, i. e., those areas receiving the pressures, stresses and strains of attachment, are laminated with and reinforced by fiber glass cloth.

It becomes evident from the foregoing that since the buttons or washers 17 are in effect integral and homogeneous with the resin of the body of the cover they constitute isolated and limited reinforced areas having their faces situated in and flush with the opposed surfaces of the associated wall of the cover. Being reinforced and having a much greater diameter than that of the concentric passage 18 provided in the button or washer for the projection of the screw 29 therethrough, all attaching pressures and forces are confined to the button or reinforced area. Since the button or washer 17 is reinforced as aforesaid throughout its mass it may be countersunk, as at 19, not only Without damage to it but also without injury to the resin body of the cover The reinforcing tape or strip 21 becomes not only integral with the inner surface of the edge portion of the cover 10 but also becomes integrally apart of each fiuottimor" Washer" 17, reinforces tlfe entire line orattachmentand additionally; supports each 1 b tttti'1"qi' washer 17 in its operative position"; chancethe efigeiofany button 17f should fail; to entirely adhere to and become one with"tl'1e"edgeof tlre opening '16 'in' which itis seated. I

Moreover; theprOv'ision of -integral and. homogeneous reinforced areas in the"coverf iiino way'interfere's visibility through the major portion of the cover;

The method and process that can'b'eemployed'in'fabri eating the casing or c'oye'r '10 to incorporate therein the features of this invention,- isas follows.

First: The transparent cover'mis fornied'to the re quired shape *by following any'applicabletecnni nei In the example shown it is generally"U-shapedin' section and forms'a continuation f" thetop and bottom skins of' thewing 11* a s'wel l as thef lea'ding edge a'nd'tip the'rof as'illustrate'd'in"Fig.- 1. Itm'ay, however; have any' "desi'red" shape and formairdif desired, cambe'mereiy a fla'torcurved panel. 7 I V second: The" cover 10, after} formation; is pierced" at spacedand'selectd intervals alongits' etigeportion's with small pilot openings which, whenfthecover or asing is in-it's operativep'osition'; respectively, align'with the openings" 14 of underlyingribs or sp'ars"'1'3 and with the openings inthe" plate nuts15"'thereon:

Third-i Using these pilot openings as'guidfesa'nd certters" tli'eenlarged openings" 16* areformed at allp'o'ints of attachment fortlre reception of the buttons 'o'r'wa'shers 173' Fourth: In the m'eantirne"' layers" offibet glass cloth are assembled one-on the other and are thoroughly impregnatwwithacrylic"resin'di'ssolved in"a'cet'oi1'e'or other volatile solvenfto form a largesheet having the approximatethickness of a finished=- button or washer; 18, i. Ct, thethickness of the resin of thewall 10 ofl-the cover 10. After this laminated sheetis fully; cured a plurality, of washers are cut therefrom; each washer having-a smallpilot hole formed centrally thereinifor alignmentjwithan aperture 14 of the coacting rib or spar13.

Fifth: The washers or buttons arev then immersed in the 'cementformed of acrylic resin dissolved in'aceton'e, or other volatile solvent, until its" exposed surfaces; includingits edge, are thoroughly impregnated with this cement and thereby become softened, whereupon the buttons 17 arein'divi'du'ally-inserted in the several en larged openings 16 providedalongitlier-edge portions of thecover IO -for thereception: thereof! It maybevad vantageous to prepare the opening 16 prior to their sertion" of" the: buttons orwashers 17 therein; treating the edge thereofwith the 'aforesaid cement.- v

Sixth: The tape or reinforcing tstr-ip' iss-alsof fabricated by impregnating one or more laminations of fiber glass cloth with the aforesaid cement, consisting of acrylic resin and a suitable volatile solvent, such as acetone, whereupon the strip or tape 21 may be applied to the inner surface of each edge portion of the cover or casing 10 to underlie the several buttons or washers 18 situated therein.

Seventh: Clamping pressure may then be applied to the edge of the casing or cover 10 and the reinforcing strip or tape 21, as well as between the buttons or washers 17 and the reinforcing strip or tape 21.

Eighth: The assembly is allowed to cure while the aforesaid pressures are maintained thereon with the result that the reinforcing strips or tapes 21 and the acrylic resin of the cover or casing 10, and also the washers or buttons 17 merge to produce an integral, unitary homogeneous mass of acrylic resin, localized or restricted areas of which viz: the buttons or washers 17 and the reinforcing strips or tapes 21, are reinforced by the inclusion of the laminations of fiber glass cloth or similar woven material; and

Ninth: The pilot opening in each button or washer 17 is enlarged to the diameter of the screw, bolt, rivet 6 or o'tlicf'fasten'ingnieans'zfto beireceived therein; and the outenface" thereof is concentrically countersunk, as at 19;, to provide there'ce'ss or'cavityforttre"snu'g and complete reception' of the head 'of the bolt; rivet 'oi'sc'rew 22; In this manner the outer surface of"th'e'cover"or casing 1'0"constitutes' a 'flush' continuation of theadj'a'cent skin'12 ofthe wing and no "projections are present at the'points 'of' attachment of the covero'r casing.

In thedisclosure of one'a'claptation ofthepre'senfim vention, screws are shown as attaching the cover or c'as ing 10 to the ribs' orspars 13, and'the countersink" 19 in each washer'or'hutton' 17 is=designed to'rece'ive'tl'i'e headof' thisscrew; It is of course to be understood that any other suitable type of atta'chin'g'means may be employedand that the countersink a't'th'e'outer extremity 'of each passage 18 of the button or Washer. 17 is to conform exactly 'to the" head of the attachin'g'ele ment so that it will be receivedcompletelyfwithin the countersink19withitsouter surface'lyingin th'eplane ofthe outer'su'rfaceof'the button or washer'17.

Manifestlmr all' of the attaching forces are" exerted throughthe buttons orwasher's' 17" and the reinforcing strips or tapes 21 these' elements are" reinforced by the inclusion th'ereinoflayers' or' laminations of fiber glass clotl'ror equivalent woven material. The impregnation of the fiber glass'cloth' or its equivalent, witlr'the same resin asis'us'e'd inthe fabrication o'fa cover or casingll) causes the adjoining faces ofthe 'strip's'or tapes 21 and the surfaceof'thecover or casing 10 to merge into a unitary and homogeneousmass and this is also'truewherethe edgewrthe-washer or'but'ton 17 contacts and'merges withth e wall of theaperturelo andbetween the face of; the" b utto'n or "washer 17 and" theadjoiningsurface of thetap'ewr reinforcing strip-211 Thus, regardless qfthe fabrication of the structure. the resultinga'ssetnb'ly; tforall practical purpo'ses, becomes'a single, homogeneous mass of acrylic resin-"with portions or restricted areas thereof reinforced by-fiber glass cloth orequivalent Woven mate'- rial;

Wiiat is claimedis: 4

1. The method of fabricating,and'locallyreinforcingan a'rti'cle madeof synthetic resin to removably secure it to a'n'aircraft component to form an" aerodynamically clean continuation thereof consisting in perforating the edge porticn'of the article with'a series 'ofope'nings' at selected points; forming button'sof woven material laminated with the'sarne resin'a s' that of the article, each button being of af shape and size conforming to said openings and h'avingia thickness equalto the thickness-of the'edg'e portion'of the article; treating"the'edges'ofsaid buttons with a cement composed of" the 'sarne'syntlietic resin'a's the-article and-a voltatil e solvent; sea-ting' 'each huttonso treated in an opening of the article, retaining the buttons in the openings of the article with their edges in flush abut-' ment with the edges of the openings until the solvent of the cement evaporates and the resin of the buttons and that of the article homogeneously unite, forming a tape of woven material laminated with the same resin as that of the article, treating one face of the tape with the cement aforesaid, retaining said treated face of the tape in flush contact with one surface of the article and with the faces of all of the buttons until the resin of the tape, article and buttons unite in a homogeneous assembly, and forming a hole centrally through each button and through the tape whereby fastening means may pass through the button and tape and engage the aircraft component.

2. The method of locally reinforcing an article fabricated of acrylic resin for the purpose of removably securing it .to associated structure consisting in perforating the article with a plurality of spaced openings, forming buttons of the same resin as that of the article laminated with a reinforcing material each having a contour conforming to the contour of said openings and a thickness substantially equal to that of the resin of the article,

forming a tape having a composition identical to that of the buttons, applying a cement comprising acrylic resin and a voltatile solvent to both the edges of each button and each opening and to one face of the tape, positioning each button so treated in an opening in the article with the edges of the button and opening in flush abutment and the treated face of the tape in flush contact with one surface of the article and each button situated as aforesaid, retaining the tape and each button thus positioned until the solvent of the cement evaporates and the resin of the tape, the button and the article unite in a unitary, homogeneous assembly, and centrally perforating each button for the reception of fastening means to engage the associated structure.

3. The method of fabricating and locally reinforcing an article made of acrylic resin consisting in piercing the article with a series of openings at selected spaced points along the edges of the article, laminating one or more layers of woven material with acrylic resin, forming a member from said laminated resin agreeing in size and shape to the size and shape of each opening, applying a cement comprising acrylic resin and a volatile solvent to the edge of each said member, inserting one member into each opening and retaining it in this position until the solvent of the cement has evaporated, laminating one or more layers of woven material with acrylic resin to create a laminated resin tape, moistening one face of the tape with a cement comprising acrylic resin and a volatile solvent, applying that face of the tape so moistened to one face of the article and in contact With corresponding faces of all of the members situated in the aforesaid openings in the article, and retaining the tape in this position until the solvent of the cement evaporates and the resin of the tape, members and article unite in a unitary and homogeneous assembly.

4. The method of fabricating and locally reinforcing an article made of acrylic resin consisting in piercing the article wtih a series of relatively small pilot openings at selected spaced intervals along an edge of the article, concentrically enlarging each pilot opening to create a series of spaced relatively large openings along said edge of the article, laminating layers of Woven fiber glass with acrylic resin to a thickness equal to the thickness of resin of the article adjacent the openings in the edges thereof, piercing said laminated resin with a relatively small pilot opening, forming a series of members from said laminated resin concentrically around each pilot opening to conform in contour to the contour of the openings in the article, applying a cement comprising acrylic resin and a volatile solvent to the edges of said members, inserting one member so treated into each of said openings and retaining it in this position until the solvent of the cement has evaporated, laminating one or more layers of woven fiber glass with acrylic resin to create a laminated resin tape, moistening one face of the tape with a cement comprising acrylic resin and a volatile solvent, applying that face of the tape so moistened to one face of the article and in contact with the faces of all of the members situated in the aforesaid openings at the edge of the article, retaining the tape in this position until the solvent of the cement evaporates and the resin of the tape, members and article unite in a unitary integral and homogeneous assembly, concentrically enlarging the pilot opening in each member and extending this enlarged opening through the tape, and countersinking that face of each member opposed to the tape concentrically with the enlarged opening therein.

5. The method of locally reinforcing an article of synthetic resin consisting in perforating an edge portion of the article at selected spaced locations with a series of openings, forming buttons of woven material laminated with the same resin as that of the article and having a shape and area to snugly fit Within each of said openings and having a thickness equal to the thickness of the edge portion of the article, securing a button thus formed in each opening in the article by cementing its edges to the edges of the opening, forming a tape of Woven material laminated with the same resin as that of the article, and homogeneously bonding one surface of the tape thus formed to one face of the article and to the face of each button situated in the aforesaid openings in the article whereby the resin of the tape, the article and the buttons unite in a unitary and homogeneous assembly.

References Cited in the file of this patent UNITED STATES PATENTS 2,366,274 Luth et al Jan. 2, 1945 2,421,096 Vogt May 27, 1947 2,430,076 Pollock Nov. 4, 1947 2,458,032 Simon et al Jan. 4, 1949 2,482,265 Gonda Sept. 20, 1949 2,482,339 Hibbard et al Sept. 20, 1949 2,511,168 Martin et a1 June 13, 1950 2,620,852 Forbush Dec. 9, 1952 2,622,052 Chandler Dec. 16, 1952 2,696,451 Snyder Dec. 7, 1954 OTHER REFERENCES Lucite Manual, by E. I. du Pont de Nemours & Co., Wilmington, Delaware, published November 1942, pages 72-78.

Repairing Reinforced Plastics, article by S. S. Oleesky, published February 1952 in Modern Plastics, pages 99, 100, 102, 104 and 106. 

1. THE METHOD OF FABRICATING AND LOCALLY REINFORCING AN ARTICLE MADE OF SYNTHETIC RESIN TO REMOVABLY SECURE IT TO AN AIRCRAFT COMPONENT TO FORM AN AERODYNAMICALLY CLEAN CONTINUATION THEREOF CONSISTING IN PEFORATING THE EDGE PORTION OF THE ARTICLE WITH A SERIES OF OPENING AT SELECTED POINTS, FORMING BUTTONS OF WOVEN MATERIAL LAMINATED WITH THE SAME RESIN AS THAT OF THE ARTICLE, EACH BUTTON BEING OF A SHAPE AND SIZE CONFORMING TO SAID OPENINGS AND HAVING A THICKNESS EQUAL TO THE TH ICKNESS OIF THE EDGE PORTION OF THE ARTICLE, TREATING THE EDGES OF SAID BUTTONS WITH A CEMENT COMPOSED OF THE SAME SYNTHETIC RESIN AS THE ARTICLE AND A VOLATILE SOLVENT, SEATING EACH BUTTON SO TREATED IN AN OPENING OF THE ARTICLE, RETAINING THE BUTTONS IN THE OPENINGS OF THE ARTICLE WITH THEIR EDGES IN FLUSH ABUTMENT WITH THE EDGES OF THE OPENINGS UNTIL THE SOLVENT OF THE CEMENT EVAPORATES AND THE RESIN OF THE BUTTONS AND THAT OF THE ARTICLE HOMOGENEOUSLY UNITE, FORMING A TAPE OF WOVEN MATERIAL LAMINATED WITH THE SAME RESIN AS THAT OF THE ARTICLE, TREATING ONE FACE OF THE TAPE WITH THE CEMENT AFORESAID, RETAINING SAID TREATED FACE OF THE TAPE IN FLUSH CONTACT WITH ONE SURFACE OF THE ARTICLE AND WITH THE FACES OF ALL OF THE BUTTONS UNTIL THE RESIN OF THE TAPE, ARTICLE AND BUTTONS UNITE IN A HOMOGENEOUS ASSEMBLY, AND FORMING A HOLE CENTRALLY THROUGH EACH BUTTON AND THROUGH THE TAPE WHEREBY FASTENING MEANS MAY PASSTHROUGH THE BUTTON AND TAPE AND ENGAGE THE AIRCRAFT COMPONENT. 